Plastic splint



March 19, 1968 J. T. HILL ETAL 3,373,741

I PLASTIC SPLINT Filed March 19, 1965 2 Sheets-Sheet l Fla. 5

)Awuis T \\\LL DONALD [2, \MGENFTO 250 LEQNAQD QE EEZ M. MAQ6ETL5 figATTORNEY March 19, 1968 J. "r. HILL ETAL 3,373,741

PLASTIC SPLINT Filed-march l9. 1965 2 Sheets-Shee 2 JAM res T DONALD Q.\N 6EI\1\TO FCZEO LEONARD E TER M- MAQGET ATTORNEY 3,373,741 PLASTICSPLINT James T. Hill, Bowie, Md., Donald R. Ingenito, Washington, D.C.,and Fred Leonard, Bethesda, and Peter M. Margetis, Silver Spring, Md.,assignors t the United States of America as represented by the ArmyFiled Mar. 19, 1965, Ser. No. 441,389 8 Claims. (Cl. 12890) theSecretary of ABSTRACT OF THE DISCLOSURE The invention described hereinmay be manufactured and-used by or for the Government for governmentalpurposes without the payment to us of any royalty thereon.

In the emergency treatment of broken bones, dislocations and sprains,splints are required to render the injured member immobile while thepatient is being transferred to a hospital or other place for thenecessary medical treatment. Splints also are used in the treatment ofinjuries such as sprains and dislocations in which a permanent cast isnot required. In the particular instance of battle wounds and injuriessustained in inaccessible places, such as those sustained in skiing,hunting or mountain climbing accidents, it is desirable that the splintbe light weight and compact. It is also desirable that the splint beapplicable under adverse conditions of light and Weather. In addition,especially in the case of battle wounds, the splint should be capable ofbearing a load so that the injured party may, after having the splintapplied, leave the scene of the injury under his own power.

The emergency splints presently used by the Army are generally eitherbasswood splints or wire ladder splints. Both of these splints are bulkyand must be heavily padded before use. As opposed thereto, the splint ofthis invention, before application, is a unitary, flexible structurecapable of being folded or rolled into a compact package and weighsapproximately 0.9 pound.

It is accordingly an object of this invention to provide a unitaryself-contained splint package.

It is another object of this invention to provide a lightweight compactsplint.

It is further an object of this invention to provide a light weight loadbearing splint.

These and other objects of the invention will be obvious from thefollowing description of the invention with reference to theaccompanying drawings wherein:

FIG. 1 is a perspective view of one embodiment of the invention;

FIG. 2 is a perspective view of the splint of the invention used in thetreatment of a knee injury;

FIG. 3 is a perspective view of an embodiment of the invention employinga foam forming resin;

FIG. 4 is a perspective view of a splint for use on an injured jaw; and

FIG. 5 is a perspective view, partly cut away, of a packaged splint.

Broadly the objects of this invention are accomplished when the splintcomprises a closed envelope containing at least two separate anddistinct materials maintained separately, the materials when mixed beingcapable of forming a cured plastic resin composition. As will bedescribed more fully below, blowing agents and reinforcice ing means mayalso be incorporated in the envelope when needed.

The essential characteristic to be considered in choosing the materialused for the envelope is that it be insoluble in, non-reactive with andnon-permeable to the materials used to form the cured resin. Suitablematerials consist of most of the commercially available packaging films.Polystyrene and Pliofilm, however, which tend to be soluble in urethanesystems containing tolylene diisocyanate therefore should not be usedwith such systems. The films can be heat scalable or capable of adhesivebonding and may either be single layers or laminated. Films which can beused either alone or in lamination are cellophane, cellulose acetate,polyvinylidene chloride, polyvinyl chloride, polypropylene, polyethyleneand polyesters. A particularly good laminate consists of orientedpolyestenpolyvinylidene chloride-polyethylene since the individuallayers provide distinct advantages in the film. The polyester suppliestoughness to resist tearing when the envelope is kneaded; thepolyvinylidene chloride provides a water vapor barrier to protectwater-sensitive isocyanate components and the polyethylene permits heatsealing. Aluminum foil also can be incorporated in a laminate to reducewater vapor permeability.

The resin systems usable in the invention are quite varied. Theessential criteria in their choice being that they cure to form ahardened solid upon the mixture of the separate components of the systemwithout the application of heat. Foam systems that do not require theapplication of heat from an external source to accomplish blowing areusable in certain embodiments of the invention. Broadly, polyester,epoxy and polyurethane resin systems have been found to be particularlyeffective in this invention.

According to the invention, the precursors of the cured resin aremaintained physically separated in individual compartments in the splintenvelope until the splint is to be formed at which time they are mixed,formed to shape and allowed to cure.

The precursors, depending upon the resin system used, may comprise thebasic materials from which the cured resins are formed or they may beprepolymer or partial prepolymer systems.

For example, when a polyester resin system is used one compartmentcontains the uncured resin and a promoter, if necessary, and the othercompartment could contain the catalyst. With epoxy resins onecompartment contains the uncured resin and the other compartment thecuring agent. With polyurethane foam systems one compartment contains apolyisocyanate and the other compartment contains a polyol resin, ablowing agent, a surfactant and catalyst.

A prepolymer system is one in which the polyisocyanate and polyol arepermitted to react in advance, with the polyisocyanate being present inexcess in the product. This product is in the first compartment and thesecond compartment contains blowing agent, surfactant and catalyst. Insuch a system, the amount of material in the second compartment is verysmall, being in the order of 1-10 parts of the mixture to partsprepolymer and permits the second compartment to be in the form of acapsule within the prepolymer compartment.

A quasi or partial prepolymer system is similar to the prepolymer systemexcept that only part of the polyol is reacted with the polyisocyanateto form the product in the first compartment and the second compartmentcontains polyol resin in addition to the materials of the prepolymersystem.

Polyester resins usable in this invention are those unsaturatedpolyester resins generally based on dibasic acids or anhydrides anddihydric alcohols which are capable a of crosslinking with vinylicmonomers to form thermoset materials. Examples of suitable dibasic acidsand anhydrides include maleic anhydride, phthalic anhydride, adipicacid, succinic acid and fumaric acid. Typical dihydric alcohols includeethylene, propylene, diethylene and dipropylene glycols. Polyhydroxylalcohols such as glycerol and pentaerythritol can be used to introducebranching in the polyester chains. Monomers added to the resins whichserve to reduce their viscosities and which are reactants incrosslinking of the resin include styrene, methyl methacrylate, diallylphthalate and triallyl cyanurate. The type of resins defined above formthe first component of a polyester system.

Catalysts or initiators are used to actuate the crosslinking processthrough a free radical mechanism which involves the opening of thedouble bonds of the polyester chain and/or the monomer. Typicalcatalysts include peroxides such as benzoyl and lauroyl peroxide andhydroperoxides such as cumene and tertbutyl hydroperoxide andmethylethylketone peroxide.

Accelerators are used to promote release of free radicals and includemetallic salts such as cobalt and manganese naphthenate, anilines suchas diethyl and methyl aniline and mercaptans such as dodecyl mercaptanand mercaptoethanol.

The common epoxy resins are produced by the reaction of epoxy compoundswith dihydro phenols, for example reacting epichlorodydrin withbisphenol A. In this invention only liquid resins can be used,commercial examples of which are Epon 815 and 828 available from ShellChemical Corporation and ERL 2795 available from Union Carbide. Theseresins are contained in one compartment and the curing agent or catalystwhich may be amines, anhydrides or acids is in the second compartment.In this invention catalysts, such as the polyfunctional aliphatic amineswhich cause rapid reaction, are required: examples of which arediethylene triamine and diethylamino propylamine.

With respect to the polyurethane foam systems described above,polyisocyanates useful in this application include 2,4-tolylenediisocyanate, 2,6-tolylene diisocyanate and mixtures of these isomers;p,p-diphenylmethane diisocyanate; m-phenylene diisocyanate;1,5-naphthalene diisocyanate; hexamethyiene diisocyanate; dianisidinediisocyanate; polymethylene polyphenyl isocyanate; and diphenylmethane4,4'-diisocyanate.

Polyol or polyhydroxy compounds usable in the above systems includeethylene and propylene oxide adducts of polyfunctional active hydrogencompounds such as glycerine, sorbitol, trimethylolpropane, ethylenediamine, sucrose, etc., and generally referred to as polyethers. Anotherclass of polyhydroxy compounds usable in the above systems are thehydroxyl terminated polyesters made by the esterification of polybasicacids with polyhydric alcohols.

Blowing agents useful in this invention include water, which reacts withthe isocyanate producing carbon dioxide, and other materials whichgenerate a gas when mixed.

Catalysts useful in these reactions include amines, particularlytertiary amines, e.g., N-methyl morpholine, triethyl amine, triethyldiamine (l,4-diazobicyclo-(2,2,2)- octane): organometallic compounds arelikewise useful as catalysts, e.g., stannous octoate, dibutyltindilaurate, lead naphthenate, cobalt naphthenate, tributyl inmethacrylate. Certain synergistic combinations of catalysts are known tothe urethane foam industry and can be usefully employed in thisapplication, e.g., organotin and tertiary amine combinations.Concentrations of these catalysts ranging between .1 and percent can beused, and this concentration may be varied to vary the reaction time.

Useful surfactants include organo silicon compounds such as dimethylpolysiloxane and polyalkylene ether copolymers. Commercial products usedinclude Union Carbide Corporations L-520, L53l, General ElectricCorportions XI -1066 and SF-1034 and Dow Cornings 113.

t These materials function to promote fine, uniform cell formationwithin the foam.

Polyurethane foam materials can be formed using these processes in awide range of foam densities. Foam densities useful in this inventionrange from 4 to pounds per cubic foot.

In all of the above systems the material should be chosen so that theresin cures within a time suitable for the condition under which thesplint is to be used. For use in battle wounds or emergency accidenttreatment, a rapid cure is essential and polyester or polyurethanesystems that cure within 10 minutes are desirable. When used inhospitals or places where time of cure is not of the essence, epoxysystems, which have cure times in the order of hours, are suitable.

Referring now to FIG. 1, one embodiment of the invention consists of aclosed flexible envelope 1, formed from a laminate of 3 mil polyethyleneand 1 mil mylar heat sealed around the edge having two compartments 2and 3 formed at one end thereof. The compartments may be formed by aweak heat seal across the width of the envelope or by a weak adhesivebond or by means which pinch off an area across the width of theenvelope. The preferred embodiment employs split resilient cylinderseparators 4 and 5 which engage folds 6 and 7 of the envelope formedaround cylinders and 51. Each compartment contains a precursor of acured polyester resin system or of a cured epoxy resin system.

The other portion of the envelope contains, coextensive therewith, areinforcing mat 8. The mat is preferably made of 4 layers of wovenfiberglass but other woven, knitted or matted textiles such as nylon,Dacron, cotton or Orlon may be used. The lower portion of the envelopehas secured thereto thick flexible pad 9 which serves as padding toprevent irritation of the patient and also serves as insulation toprotect the patent from the heat liberated during the curing process.Pad 9 can, for example, be made from A" flexible polyurethane foamadhesively bonded to the envelope by an adhesive on the foam.

In use, the separation between compartments 2 and 3 is removed bybreaking the bond forming the separation or by removing separator 4 andthe precursors in the two compartments are mixed thoroughly. Aftermixing is completed, the remaining separator 5 is removed and thecontents worked uniformly into the remaining section of envelope 1 toimpregnate mat 8 with the mixture. After the mat 8 has been impregnatedwith the resin, the split is placed in contact with the injured member,with the pad 9 contacting the body, and formed to the desired shape. Thesplint is then fastened in place by means of straps 10 as shown in FIG.2.

Suitable precursor compositions for a polyester resin system are setforth below:

Example 1 Compartment 2:

Laminac 4110 g 200 Vibrin Promotor #3 ml 5 Compartment 3:

Benzoyl peroxide paste (50% in tricresyl phosphate) gm 4 Example 2Compartment 2:

Epon 815 g- 200 Compartment 3:

Epon curing agent T-1 g 50 Both components are available from ShellChemical Corporation, Epon 815 being a liquid epoxy resin with aviscosity of about 700 centipoise and an epoxide equivalent of 175-195and the T-l curing agent being an aliphatic polyamine. Cure wassufiicient to yield a weight bearing splint after 4 hours.

The splint package used when a foam resin system is employed differsfrom that already described basically in that the mat 8 is notincorporated into the envelope.

As shown in FIG. 3, the envelope 1 has two compartments 2 and 3 formedat one end thereof by separators 4 and 5, each compartment containing aprecursor of the foamed resin. The pad 9 is secured to envelope 1 up tothe edge of compartment 3. The pad is equal in length to the wholeenvelope and that portion coextensive with compartments 2 and 3 has astrippable sheet 12 adhered thereto. In use, the precursors are mixed asdescribed above until the mixture takes on a whitish appearance andthere is a noticeable evolution of heat. The other separator is thenremoved and the foaming resin worked uniformly through the envelope 1.The backing 12 is removed and pad 9 is adhered to the portion of theenvelope that previously formed compartments 2 and 3. The splint is nowready for application and is placed in contact with the injured member,shaped and fastened as described above.

Suitable precursor compositions, a polyurethane foam system, are asfollows:

Example 3 Compartment 2:

Isofoam 15-A gm 150 Compartment 3:

Isofoam 15W gm- 113 Stannous octoate mg 9 Triethylene diamine mg 9 TheIsofoam materials were obtained from the Isocyanate Products Co. and theabove mixture yielded a weight bearing splint with a foam density of 18pound/ft. six minutes after mixing of the precursors.

The above examples have been described with respect to a splint for alimb injury and the envelopes for such application are about 26" longand 8" wide. However, the splint of this invention can be made indifferent configurations for various uses. Referring now to FIG. 4 asplint package for a jaw injury is illustrated.

In this embodiment, the envelope 21 is formed into the shape shown withthe central opening 22 heat sealed around the edges. A foam pad 23 ofthe same configuration as envelope 21 is adhered to one surface of theenvelope 21. The envelope 21 contains a liquid prepolymer 24 having anexcess of isocyanate and a blowing agent, catalyst, surfactant mixtureis contained within rupturable capsule 25, The capsule can be formed ofthe same material as envelope 1. In use the capsule 25 is ruptured, thecontents mixed with the prepolymer 24 until the mixture turns white andheat is evolved. The mixture is distributed evenly throughout theenvelope and then applied with the subjects jaw in the central opening22, formed to shape and then held in place with adhesive tape or tied bystraps.

In the above splint approximately 50 grams of a liquid prepolymercontaining excess polyisocyanate is contained in the envelope and thecapsule contains 2 gms. of water, 2 gms. of triethylene diamine and 9mg. of stannous octoate.

Before curing the splint, envelopes can be rolled into a compactcylinder and packaged in a tubular container 30 together with theadhesive or other type of straps 11 used to fasten the splints as shownin FIG. 5.

While this invention has been disclosed with respect to severalembodiments thereof, the invention is not limited thereto and includesall modifications thereof within the scope of the following claims.

We claim:

1. A splint package comprising a flexible sealed envelope having aflexible pad attached to one face thereof substantially coextensivetherewith, the interior of said envelope being divided into at least twocompartments by removable separating means, a first compartmentcontaining a first material and a second compartment containing a secondmaterial, said first and second materials being precursors of a curedresin system and which, when mixed, will cure without the application ofexternal heat.

2. The splint package of claim 1 wherein the interior of said envelopeis divided into three compartments, the third compartment containing,coextensive therewith, flexible reinforcing means and wherein said firstand second materials are precursors of cured resin systems selected fromthe group consisting of polyester resins and epoxy resins.

3. The splint package of claim 2 wherein said reinforcing means is awoven fiberglass mat.

4. The splint package of claim 1 wherein said first and second materialsare precursors of a foamed resin system and one of said materialscontains a blowing agent.

5. The splint package of claim 1 wherein at least one of said removableseparating means comprises a resilient member in clamping engagementwith a fold across the width of said envelope.

6. The splint package of claim 1 wherein at least one of said separatorscomprises a rupturable capsule contained within one of saidcompartments.

7. The splint package of claim 1 wherein the interior of said envelopeis divided into three compartments, said third compartment beingsubstantially longer than the combined lengths of said first and secondcompartments and said flexible pad is attached to the face of saidenvelope coextensive with said third compartment.

8. The splint package of claim 7 wherein the flexible pad extends alongthe length of said first and second compartments and the portion of saidpad coextensive therewith has an adhesive surface covered by a removablesheet.

References Cited UNITED STATES PATENTS 2,700,461 1/1955 Smith 206472,864,492 12/1958 Lappala 206-47 2,874,830 2/ 1959 Birmingham 206-47RICHARD A. GAUDET, Primary Examiner. J. W. HINEY, Assistant Examiner.

